Peter wrote in message ...
Doug Carter wrote
Keep in mind that GPS is a broad band spread spectrum waveform, not a
narrow band FDM channel like a VOR uses.
GPS is a narrow band signal.
One implication (and the
principal reason military customers like spread spectrum system) is the
difficulty in jamming. Depending on the coding gain and distance it
takes a lot of transmitter power. However, power amplifiers (even at L
band) are commercially available so it can be done.
1 watt at 30,000 feet (e.g. hanging under a very low cost baloon) will
jam GPS over a radius of about 500 miles.
Reference already discussed in this thread.
Peter.
--
http://www.mayflowercom.com/testresults.htm
a recent Lincoln Laboratory study (Gilmore and Delaney [2]) indicated that
a modest 1 W in-band interference source may deny C/A code receiver
operation up to a range of about 85 km.
I get 53 miles.
These guys say you are off by a factor of ten.